1. Field of the Invention
The subject invention relates to polyol compositions which are alkylene oxide adducts of vicinal toluenediamine. The subject polyol compositions are prepared by a two-step process and are particularly useful in the preparation of rigid polyurethane foams.
2. Description of the Prior Art
Alkylene oxide adducts of various aromatic amines are well known in the art. It is also known that such adducts can be used in the preparation of polyurethane foams.
Generally alkylene oxide adducts of aromatic amines are prepared by reacting an alkylene oxide with an aromatic amine at temperatures of 90.degree. C. to 125.degree. C. in the presence of an alkoxylation catalyst. These temperatures are preferred in order to avoid undesirable side reactions which decrease the yield of the desired product. Moreover, low levels of catalyst (0.2 part or less per 100 parts of amine) are also preferred because this reduces the time and expense needed to remove the catalyst.
It is also known that such adducts can be prepared by adding the alkylene oxide in two steps. For instance, U.S. Pat. No. 4,209,609 shows the preparation of an alkylene oxide adduct of 2,4-toluenediamine and 2,6-toluenediamine using a two-step alkoxylation process whereby from 3 to 5 moles of ethylene oxide are reacted with the toluenediamine and then 1 to 5.1 moles of propylene oxide are reacted with the adduct prepared in accordance with the first step.
None of the disclosures in the prior art, however, teaches or suggests the preparation of alkylene oxide adducts of vicinal toluenediamine nor do they suggest the reaction conditions specified herein. As will be demonstrated herein, it has been found that alkylene oxide adducts of vicinal toluenediamines prepared under the specified reaction conditions have lower viscosities than alkylene oxide adducts prepared from other isomers of toluenediamine, and that such adducts of vicinal toluene diamine have lower viscosities than those which are not prepared in accordance with the reaction conditions specified herein.